DESCRIPTION: Studies of the evolution of the viral population following the initiation of anti-retroviral therapy have revealed a dynamic pattern of virus production and cell turnover that has important implications for viral pathogenesis. These new concepts of vial dynamics will provide important information about virus escape from combination antiretroviral therapy and cytotoxic T-lymphocyte killing. In this application, a systematic analysis of plasma virus will provide an indication of the replication events in lymphoid tissue as well as the significance of the plasma virus as a mediator of viral pathogenesis.